HOUSTON — Undocumented Mexican immigrants living near the California-Mexico border experience increased rates of clinical depression and anxiety, a new study finds.

Researchers at Rice University examined the incidence of mental illnesses and substance abuse among 250 individuals within this stressed population, finding that 23 percent met the DSM’s criteria for having a mental disorder.

Fourteen percent of the study’s participants were found to have major depressive disorder (MDD), while eight and seven percent had panic or generalized anxiety disorders, respectively.

Some were determined to have suffered from multiple conditions concurrently.

“The estimates obtained in this study for depression and anxiety disorders were considerably higher in this population when compared with estimates for the general U.S. population,” says lead author Luz Garcini in a university news release.

Namely, one major study shows that seven percent of Americans suffer from MDD, while three percent suffer from a panic or anxiety-related disorder.

These findings came despite the related finding that aliens residing in the U.S. did not demonstrate increased levels of substance abuse.

“This finding defies existing stereotypes that contribute to stigmatization of and discrimination against Mexican immigrants living in the U.S. without documentation as a population with high prevalence of substance use,” Garcini explains. “These individuals are unlikely to engage in substance use because it increases their risk for deportation and it interferes with their productivity at work.”

The researchers believe that a number of stressors, including stigmatization, language barriers, fear of deportation, family separation, and discrimination, are culprits for the deteriorated mental health of many migrants.

“Additional research and funding are needed to document the devastating effects of the current socio-political context on the mental health of immigrants living in the U.S. without documentation, which is needed to inform advocacy, policy and intervention efforts,” Garcini concludes.

The study’s findings will be published in a future issue of the Journal of Consulting and Clinical Psychology.